I remember at one of the Apple events Steve Jobs was saying the one area of complexity that still hung people up was the filesystem, so iOS (and as an extension, iPadOS) hid it away from the user. Files were locked to apps. As the platform evolved, people wanted/needed to operate in multiple apps with one file, so this concept of duplicating files in multiple apps came to be. This was a mess when it came to file versioning. It was also very difficult and confusing, and required apps to support it.

Eventually they added the Files app, but it is a very slow road to change over from an app based system to a file based system. Even today, it’s a crap shoot and some apps work better with the Files app than others, and it seems this aspect is still much more confusing than macOS from this perspective.

This was a huge miss that no one really talks about.